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748086b7 | 1 | /* Copyright (C) 2005, 2009 Free Software Foundation, Inc. |
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2 | Contributed by Richard Henderson <rth@redhat.com>. |
3 | ||
4 | This file is part of the GNU OpenMP Library (libgomp). | |
5 | ||
6 | Libgomp is free software; you can redistribute it and/or modify it | |
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7 | under the terms of the GNU General Public License as published by |
8 | the Free Software Foundation; either version 3, or (at your option) | |
9 | any later version. | |
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10 | |
11 | Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
748086b7 | 13 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
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14 | more details. |
15 | ||
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16 | Under Section 7 of GPL version 3, you are granted additional |
17 | permissions described in the GCC Runtime Library Exception, version | |
18 | 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | You should have received a copy of the GNU General Public License and | |
21 | a copy of the GCC Runtime Library Exception along with this program; | |
22 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | <http://www.gnu.org/licenses/>. */ | |
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24 | |
25 | /* This file handles the CRITICAL construct. */ | |
26 | ||
27 | #include "libgomp.h" | |
28 | #include <stdlib.h> | |
29 | ||
30 | ||
31 | static gomp_mutex_t default_lock; | |
32 | ||
33 | void | |
34 | GOMP_critical_start (void) | |
35 | { | |
36 | gomp_mutex_lock (&default_lock); | |
37 | } | |
38 | ||
39 | void | |
40 | GOMP_critical_end (void) | |
41 | { | |
42 | gomp_mutex_unlock (&default_lock); | |
43 | } | |
44 | ||
45 | #ifndef HAVE_SYNC_BUILTINS | |
46 | static gomp_mutex_t create_lock_lock; | |
47 | #endif | |
48 | ||
49 | void | |
50 | GOMP_critical_name_start (void **pptr) | |
51 | { | |
52 | gomp_mutex_t *plock; | |
53 | ||
54 | /* If a mutex fits within the space for a pointer, and is zero initialized, | |
55 | then use the pointer space directly. */ | |
56 | if (GOMP_MUTEX_INIT_0 | |
57 | && sizeof (gomp_mutex_t) <= sizeof (void *) | |
58 | && __alignof (gomp_mutex_t) <= sizeof (void *)) | |
59 | plock = (gomp_mutex_t *)pptr; | |
60 | ||
61 | /* Otherwise we have to be prepared to malloc storage. */ | |
62 | else | |
63 | { | |
64 | plock = *pptr; | |
65 | ||
66 | if (plock == NULL) | |
67 | { | |
68 | #ifdef HAVE_SYNC_BUILTINS | |
69 | gomp_mutex_t *nlock = gomp_malloc (sizeof (gomp_mutex_t)); | |
70 | gomp_mutex_init (nlock); | |
71 | ||
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72 | plock = __sync_val_compare_and_swap (pptr, NULL, nlock); |
73 | if (plock != NULL) | |
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74 | { |
75 | gomp_mutex_destroy (nlock); | |
76 | free (nlock); | |
77 | } | |
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78 | else |
79 | plock = nlock; | |
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80 | #else |
81 | gomp_mutex_lock (&create_lock_lock); | |
82 | plock = *pptr; | |
83 | if (plock == NULL) | |
84 | { | |
85 | plock = gomp_malloc (sizeof (gomp_mutex_t)); | |
86 | gomp_mutex_init (plock); | |
87 | __sync_synchronize (); | |
88 | *pptr = plock; | |
89 | } | |
90 | gomp_mutex_unlock (&create_lock_lock); | |
91 | #endif | |
92 | } | |
93 | } | |
94 | ||
95 | gomp_mutex_lock (plock); | |
96 | } | |
97 | ||
98 | void | |
99 | GOMP_critical_name_end (void **pptr) | |
100 | { | |
101 | gomp_mutex_t *plock; | |
102 | ||
103 | /* If a mutex fits within the space for a pointer, and is zero initialized, | |
104 | then use the pointer space directly. */ | |
105 | if (GOMP_MUTEX_INIT_0 | |
106 | && sizeof (gomp_mutex_t) <= sizeof (void *) | |
107 | && __alignof (gomp_mutex_t) <= sizeof (void *)) | |
108 | plock = (gomp_mutex_t *)pptr; | |
109 | else | |
110 | plock = *pptr; | |
111 | ||
112 | gomp_mutex_unlock (plock); | |
113 | } | |
114 | ||
115 | /* This mutex is used when atomic operations don't exist for the target | |
116 | in the mode requested. The result is not globally atomic, but works so | |
117 | long as all parallel references are within #pragma omp atomic directives. | |
118 | According to responses received from omp@openmp.org, appears to be within | |
119 | spec. Which makes sense, since that's how several other compilers | |
120 | handle this situation as well. */ | |
121 | ||
122 | static gomp_mutex_t atomic_lock; | |
123 | ||
124 | void | |
125 | GOMP_atomic_start (void) | |
126 | { | |
127 | gomp_mutex_lock (&atomic_lock); | |
128 | } | |
129 | ||
130 | void | |
131 | GOMP_atomic_end (void) | |
132 | { | |
133 | gomp_mutex_unlock (&atomic_lock); | |
134 | } | |
135 | ||
136 | #if !GOMP_MUTEX_INIT_0 | |
137 | static void __attribute__((constructor)) | |
138 | initialize_critical (void) | |
139 | { | |
140 | gomp_mutex_init (&default_lock); | |
141 | gomp_mutex_init (&atomic_lock); | |
142 | #ifndef HAVE_SYNC_BUILTINS | |
143 | gomp_mutex_init (&create_lock_lock); | |
144 | #endif | |
145 | } | |
146 | #endif |